Bronzing material



Patented Feb'. 23, 1943 BRONZIN G MATERIAL Cornelius S. Fleming, LcsAngeles, Calif.

No Drawing.

19 Claims.

My invention relates to bronzing materials and particularly to methodsand materials for improving the characteristics of bronzingcompositions. The present application is a continuation in part of myearlier filed copendine' applications Serial No. 180,594, filed December18, 1937, and Serial No. 155,735 filed July 26-, 1937.

In the preparation of bronzing compositions,

such as aluminum paints and similar coatin compositions, it has beencommon practice to prepare the bronzing powder in the form of a pastesuitable for mixing with a vehicle at the time the composition is to beused. The effectiveness of the coating composition depends to.

large extent upon the property of a flaked bronzing powder to leaf outand produce an effective coverage of the surface to which it is applied.The clean flaked particles of bronzing powders, such as aluminum, do ushave the property of leafing sufficiently to be'practicable for generaluse; and it has become common practice to treat the flaked particleswith stearic or similar fatty acid, as an agent for improving theleaflng property of the powder. The stearic acid is commonly mixed withthe powder in a ball mill, the treatment being so carried out that thepowder is flaked and polished, and at the same time intimately mixedwith the leaflng agent. The material, so treated, is reduced to theconsistency of a paste; and is added to a vehicle in appro riate amountsas required.

The pastes so produced have been found to be defective in that there isa relatively rapid Application October 25, 1938, Serial No. 236,905

tors, without eliminating or satisfactorily curing the defects.

For example, vehicles comprising a varnishlike base, including gums orresin, have been used, but have been found to be defective in that theyhave lacked durability; and are injured by heat and by the presence ofmoisture.

Reasonably good leafing of, the bronzing powder has been obtained insuch vehicles when freshly mixed, but if allowed to stand for anymaterial length of time, the bronzing powder settles out as a densebody, and the ieafing property is seriously impaired, if not completelydestroyed.

deterioration of the luster and leaflng properties of the paste. Suchdeterioration occurs to some extent in theunopened containers, whenallowed to stand for a period of months; and coating compositions madefrom pastes which have stood for different periods of time, show aprogressive loss of luster and leafing properties. After opening thecontainer, the deterioration has been relatively rapid, especially ifexposed to the atmosphere; and is greatly accelerated by heat. Thepresence of moisture has been found to be very detrimental to thepastes.

The manufacture of coating compositions from such pastes has also pr,sented numerous diflicult problems which many have unsuccessfullyattempted to solve. Coating compositions, such as heretofore produced,have been defective in- .yarious ways; and efforts to'overcome onedefect have resulted in bringing about other objection- "ablecharacteristics.

practice has been confined to products which As a result, commercialrepresent a compromise between conflicting fac- Oilbase vehicles havebeen found to offer greater durability; but the difliculty in obtainingand retaining the leafing property of the bronzing powder has been evengreater than in the oil and resin base vehicles.

The films produced by such compositions have been far from satisfactory.When used as a priming coat for wood, concrete, and similar poroussurfaces, the penetration has been poor, and the film tends to pull awaywhen another coating material is applied thereover. The adherence tosmooth metal surfaces, such as iron, has been poor. There has been amarked tendency for the fllms produced from such compositions to crackor alligator, especially when applied to materials such as preparedrooflngs; and both the appearance and effectiveness have been seriouslyimpaired. Efforts to correct such defects have resulted in compositionsin which the leaflng properties of the bronzing powder has beenimpaired, and in which the luster of the bronzing powder is destroyed ifallowed to stand even for a relatively short time. No effective meanshas heretofore been known for I restoring the leaflng property andluster of the ing powder orpaste, or with a vehicle to be used withbronzing powder or paste, or with a bronzing .paint, to obtain stabilityof the leaflng property and luster of the powder.

A further object is to provide an agent having agent.

the property of restoring the leaflng property and luster to bronzingcompositions in which those properties have become lost or impaired.

Another object is to provide a bronzing composition which will withstandrelatively high temperatures; and which is not materially imnailed bythe presence of moisture either in the composition itself, or on thesurface to which it is applied; and which will retain its leaflngproperty and luster after prolonged standing and exposure.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of my invention. It is to be understoodthat I do not limitmyself to this disclosure of species of my invention, as I may adoptvariant embodiments thereof within the scope of the claims.

In terms of broad inclusion, my invention contemplates new methods andmaterials for producing a bronzing composition having stable propertiesof leafing and luster, comprising'a bronzing powder which is subjectedto the combined action of a leafing agent, a stabilizing and brighteningagent, and an anti-polymerization The leafing, stabilizing andanti-polymerization agents are preferably combined in a prepared mixturesuitable for addition to a bronzing powder or paste, or to a vehicle towhich such powder or paste is to be added, or to a paint comprising avehicle with which powder or paste has been mixed. When the preparedmixture is initially mixed with the powder or paste, or with the vehicleor the paint, a product is obtained in which the leafing property andluster will remain stable both before or after mixing in a paint. Alsothe prepared mixture may be added to a bronzing composition forrestoring the leafing property and luster to a product in which thosecharacteristics have become lost or damaged through age or exposure toinjurious influences.

In terms of greater detail the bronzing material of my inventioncomprises a bronzing powder, such as aluminum powder or paste, which issubjected to the combined action of materials increasing the leaflngproperty, luster and stability of the powder-or paste. Those materialsare preferably combined in a prepared agent and comprise a leafingagent, preferably stearic acid. Myristic acid may be substituted whollyor in part for the stearic acid. Other fatty acids of a similar naturesuch as the higher fatty acids derived from fats and oils, such aslauric acid,

the fatty acids of rapeseed, linseed, or palm and also oleic acid andthe fatty acids derived from tallow may be used, preferably in mixturewith stearicacid. The latter named fatty acids in producing leafing andimprove the penetration,

adherence, and other properties of the film produced.

With the stearic acid or equivalent leafing agent is mixed a stabilizingand brightening agent. For that purpose I have found that ButylDistolene, a commercial product composed chiefly of butyl oleate, ishighly satisfactory. Butyl stearate has also been found to giveexcellent results. In general, the esters of the fatty acids, includingthe saturated fatty acids of the series ortho-tolyl-guanidine.

while technically satisfactory, are impractical for commercial reasons.For example, the esters of the lower fatty acids, such as methyl orethyl formate or acetate have boiling points so low and are so volatileas to be impractical for commercial use. Many of the esters of thehigher and more complex fatty acids are rare; and are either notavailable, or the cost is prohibitive. For practical purposes, theboiling point of the ester should not be below 212 F. The esters ofstearic acid-such as amyl stearate, propyl stearate, methyl stearate andethyl stearate; and the butyl esters of the fatty acids of palm oil andof the fatty acid of sunflower seeds are especially For that'purpose Iprefer to use a derivative of an amidine, such as diphenyl-guanidine ordi- Phenol, or its derivatives and homologues, such as cresol, thymol,paraor ortho-hydroxy diphenyl may be used, as may also dihydric phenols,4 such as catechol or guaiacoi. Cresol derivatives such as thio-cresol,meta-thio-cresol, and similar substances may be used. Arylamines such asaniline, mono-methylaniline, and naphthylene derivatives suchasbeta-naphthylamine, beta-thio-naphthol, and similar substances may besubstituted. Mineral substances such as selenium, arsenic, sulphur,tellurium and their equivalents are also useful alone or in combinationwith one or more of the organic anti-polymerization agents.

The several ingredients of the mixture cooperate to produce a number ofbeneficial results.-

For example, where stearic acid alone Produces only. a temporary leaflngproperty, the combination of stearic acid with butyl oleate or otherequivalent ester of a fatty acid stabilizes the property. While theprecise reaction is not fully understood, it is believed that loss ofleaiing is due largely to the reaction of the stearic acid with thevehicle and the production of soaps forming a film over the powderparticles which impairs the leaflng property. The reaction is aprogressive one, and in time destroys the leai'lng property completely.The presence of a fatty acid ester retards such reaction, and tends tokeep whatever film is formed in an open condition such that the leafingproperty is not materially affected V mixed paint, the polymerizationcauses the particles of bronzing powder to become encased in a coatingof polymerized oil which destroys the leafing property. Here again theaction is a progressive one, which may be accelerated by heat ormoisture. The anti-polymerization agent of my invention acts to preventor retard polymerization, and, in combination with the leailna' andstabilizing agents, obtains a product which is sub stantially stableboth as to leaiing and luster.

The following compositions are illustrative of the prepared agent 01 myinvention:

Parts A. Butyl oleate 100 Diphenyl guani'cline 20 Stearic acid 40 B.Butyl myristate 100 Phenol l Diphenyl guanidine Stearic acid C. Butyloleate u 100 Cresol 1 0 Stearic acid Oleic acid In the foregoingexamples the ingredients are mixed and heated together to about 200 F.after which they are allowed to cool and are ready for use. Thequantities of the several ingredients may be varied through relativelywide limits, variations of as much as about being possible withoutseriously impairing. the effectivenes of the mixture.

For some purposes, particularly for use with vehicles comprising an oiland resin base, it has been found desirable to include in the mixture amoderate quantity of a natural or synthetic resin, for example apara-coumarone-indene resin such as Nevindine or Cumar gum. By way ofillus- Where a gum such as Nevindine, or Cumar gum is included themixture should be heated to about 300 F. in order to properlyincorporate th gum in the mixture. The gum acts as a carrier for theanti-polymerization agent; and aids in obtaining an effective mixturewith the vehicle of a coating composition.

Where it is desired to cheapen the product or increase its bulk, theprepared agent may be diluted with mineral spirits. In general, suchdilution is not recommended, since it either requires the use of ahigher percentage of the prepared agent, or causes an impairment of thesta bility of the bronzing composition to which it is added.

The prepared agent may be mixed directly with the bronzing powder orpaint, or it may be added to a vehicle, or to a mixture of bronzingpowder or paste with a vehicle. For example, the prepared agent abovedescribed may be incorporated with the bronzing powder in the ball millduring the process of flaking and polishing the powder. When so used,the prepared agent is substituted for the stearic acid heretoforeordinarily used in the ball mill in producing a bronzing paste. Theagent may be diluted with mineral spirits in order to obtain the desiredfluidity in the ball mill. Any excess liquid may be removed byevaporation after leaving the ball mill to reduce the mixture to a pasteof the desired consistency.

Instead of mixing my prepared agent with the powder in a ball mill, theagent may'be mixed with a bronzing powder by other methods. For example,by adding from 10 to 20 percent of my agent to a dry powder andsubjecting the mixture to a shaking action, the agent may be uniformlydistributed over the particles of powder. Upon such treatment, themixture becomes loosely flaked, and will retain its leafing property andluster for prolonged periods and under severe conditions of heat andmoisture.

Instead of initially mixing the prepared agent with the bronzing powderin a ball mill or otherwise, the powder may be flaked and polished withstearic acid in the ordinary manner and my agent added to the resultingpaste. For most purposes 10% by weight of my agent added to andintimately mixed with a paste prepared with stearic acid results in aproduct which will retain. the leaflng property and luster of the powderfor long periods of time and under extreme degrees of heat and moisture.The quantity of the prepared agent may be varied through wide limits. Aslittle as about 2% materially improves the stability, luster and leafingproperty of the paste. The amount may be increased to 20% or morewithout impairing the resulting product.

If desired, the prepared agent may be added to a vehicle intended foruse with a bronzing powder or paste. In that case, I prefer to add toany ordinary vehicle suitable for use in a bronzing paint about 5% byweight of my prepared agent. When bronzing powder or paste is then mixedwith the vehicle, the ingredients of my prepared agent act upon thebronzing powder in the mixture and produce a stability of luster andleaflng power comparable with the results obtained by initially mixingthe prepared agent with the powder or paste. The amount of agent whichis added may be varied from about 2% to 10% or more, if desired.

When the ordinary bronzing paste and ready mixed bronzingpaints'heretofore available on the market have been allowed to stand forsome time, say two or three months, a material impairment of the leaflngproperty and luster occurs. The impairment increases with the lapse oftime; and is greatly accelerated by heat and moisture. Compositionsexposed to the air lose their luster and leafing property in a veryshort time, sometimes within a few hours. When subjected to heat and/ormoisture the utility of such products may be destroyed in only a fewminutes.

Heretofore, products so impaired have been treatedas useless, since nomethod of restoring the luster and leafing property has been known. Theprepared agent of my present invention has the property of restoringleaflng and luster and producing products in which those restoredproperties are stabilized. For that purpose, from 2 to 10 percent of theprepared agent of my invention is added and intimately mixed with theimpaired product. In the case of bronzing paste in which the leafingproperty and/or luster has become impaired, such an addition of myprepared agent restores a'nd stabilizes both the leaf ing property andthe luster of the bronzing powder. After such treatment, the restoredprop erties of leaflng and luster remain stable. The

be subjected to severe conditions of heat and moisture, without materialimpairment.

In the case of ready mixed bronzing paintsin which the leailng propertyand luster of the bronzing powder has become lost or seriously impaired,the addition of about 2 to 10 percent of the prepared agent of myinvention restores and stabilizes both the leaflng property and luster.The product, so restored, is then comparable with a freshly preparedproduct made in accordance with my invention.

' While the prepared agent of my invention is adaptable for general usewith bronzing compositions employing any of the vehicles commonly usedfor preparing bronzing paints, I have found that the ingredients of thecomposition may-be incorporated in a vehicle-base during the initialcooking thereof with highly desirable results; and that products soproduced possess a number of superior qualities. By such .treatment, theadded ingredients of my invention become thoroughly incorporated withthe vehicle, and when bronzing powder or paste is subsequently added tothe vehicle a remarkably stable and effective coating material isproduced.

A vehicle so prepared preferably has as its base a drying or semi-dryingoil. Ii desired, the base may include suitable amounts of natural orsynthetic gums or resins. Perilla oil has been found to be highlysatisfactory. China-wood oil, linseed oil, oiticica oil, sardine oil,and similar drying or semidrying oils, or combinations thereof, may beused instead of perilla oil, or in combination therewith.

Any of the gums and resins commonly used in the manufacture of paintsand varnishes may be added. The synthetic ester gums such asSynthe-Copal Ester Gum, and the paracoumarone-indene resins such asNevindine and Cumar gum have been foundto be well suited for use in thevehicle of the present inventlon. Synthetic phenolic resins, alkydresins, and modified resins of the' phenolic and alkyd types, may beused, as for example: "Telac (malic acid-formaldehyde reaction product),Bakelite #4036 (phenol-formaldehyde resin), Beckacite #1112(phenol-formaldehyde resin modifled with ester gum), or "Beck-Kohler#2000 (phenol-formaldehyde resin).

To the base are added suitable amounts of a leafing agent and astabilizing and brightening agent selected from the respective groups.above noted in connection with the separately prepared agent of myinvention. In general, the amount of fatty acid and fattyacid esteradded should be from 5 to percent of the oil content of the vehicle; butthe amount may be varied through a considerable range above and belowthose percentages.

In addition, suitable amounts of an anti-polymerization agent of theclass above described is added. The anti-polymerization agent has theeffect of inhibiting reaction of the oils, gums and resins with thebronzing powder, thereby preserving the luster of the powder in thevehicle. At the same time, the anti-polymerization agents in general,have the further property of preventing jelling of oils, such asChinawood oil, as a result of heat treatment. Because of that prope'rty,an effective blending of the fatty acid and ester with the heat treatedvehicle is possible without impairment of the vehicle. .In the case ofthe mineral anti-polymerizaor increased if desired.

tion agents, only a relatively small quantity is required. About onepart of mineral per one hundred parts of oil is ample formost vehicles,but that amount may be substantially reduced In the case of the organicanti-polymerization agnts,"about five to tenparts per one hundred"partsof oil give satisfactory results in most cases, but greater or lesseramounts may be used to advantage in some cases.

The vehicle is preferably prepared by cooking the oil, or oil and gum orresin components, with the fatty acid and/or ester and anti-polymeri!zation agent, to a temperature of about 450 to thinner added at the timeof use.

500 F. in about 20 to 45 minutes. The mixture is then allowed to cool,and when the temperature has dropped to about 350 to 400 F., suitableamounts of a thinner such as mineral spirits, gasoline, naphtha, toluol,or other similar ma-' terials is stirred into the mixture. Ordinarilythe amount of thinner approximately equals the volume of the cookedmixture, but the amount may be substantiallyv increased or decreased inaccordance with the consistency which is desired in the final product.In some cases, the

thinner may be omitted entirely.

and the manner in which they are combined,

may be .varied in many ways. The following typical examples illustratevarious compositions which I have found to satisfactorily accomplish thepurposes of my present invention:

. Parts 1. Perilla oil 560 Myristic acid 40 Arsenic (AszOu); 4 Cobaltnaphthenate (6%) 30 Cook to 500 F. in 35 to 45 minutes, then allow tocool naturally. This mixture may be thinned to desired consistency whilewarm, or after cooling. Bronzing powder (1 to 2 lbs. per gallon) may beadded directly to the base vehicle, and

Parts 2. Ester gum 200 Perilla oil Arsenic (AS203) 2 Myristic acid 20Mineral spirits 200 Gasoline Cobalt (6%) naphthenate 20 Cook the gum,oil and arsenic to about 500 F. in 23' to 30 minutes.

-Add myristic acid on cooling to about 450 F.

Cobalt (6%) naphthenate Cook to 500 r. in 25 to 30 minutes. Add 300parts mineral spirits on cooling to ,about400" F.

Parts in suitable containers and stored indefinitely 4. Ester gum 80without material deterioration.

Perilla oil 200 The fatty acid and ester of fatty acid, not only Aniline20 serves to obtain stability of the leafing property Oleic acid 20 5and luster of the bronzing powder, but results Cobalt (6%) naphthenate15 in producing a superior film. For example, I

Cook to 500 F. in 25 to 30 minutes. Add 300 parts mineral spirits oncooling to about 400 F.

Cook to 500 F. in 24 to 25 minutes. Thin at 400 F. with 300 partsmineral spirits.

Parts '7. Ester gum 80 Perilla oil 200 Stearic acid Cook to 500 F. in 26to 27 minutes. Thin at 400 F. with 300 parts mineral spirits.

- Parts 8. Ester gum 40 Perilla oil 120 China-wood oil 140 Aniline 2oButyl ester of palm fatty acid Cook to 500 F. in 23 to 24 minutes.

Cool to 300 F. and add 10 parts butyl ester ofpalm fatty acid, thin with300 parts mineral spirits, and add 5 parts cobalt naphthenate'.

The proportions noted in the foregoing examples may be varied withinrelatively wide limits; and equivalent materials maybe substituted inpart or in whole for the variousmaterials specified in the examples.Fatty acid ester, for example butyl oleate or other alkyd ester such asmay be used in the prepared agent above disclosed, may be added to thevehicles of Examples 1 to 7, inclusive, in amounts varying betweenrelatively'wide limits depending upon the properties which it is desiredto impart to the product. The addition of such fatty acid ester improvesthe stability of the properties of leafing and luster of aluminum flakesmixed with the vehicle to produce an aluminum paint. At the same time,the fatty acid ester tends to retard drying of the film, and lessens itshardness. maximum stability of leafing and luster is not essential,little or none of the fatty acid ester is required. Should leafing orluster become s riously impaired in a mixed aluminum paint produced fromthe vehicle, those properties may be restored by adding suitable amountsof the prepared agent of my invention at any time behave found that thepresence of the fatty acid and ester'of fatty acid causes increasedpenetration when the composition is applied to wood, concrete, andsimilar surfaces; and a firmer bond is therefore obtained. The vehicleof my invention also obtains improved adherence to metal and similarsurfaces; and because of its flexibility and elasticity, has increasedeifectiveness and durability either as a primer, or as a finish coating.Because of the heat treatment and the composition of the vehicle, thefilm dries and sets substantially uniformly throughout, rather than'fromthe surface as in the bronzing com-,

positions heretofore commonly used. The composition is especiallysuitable for use upon prepared roofings. In that connection, thesuperior leafing properties of the bronzing powder in the vehicleinsures an effective and durable coating which does not crack oralligator."

The composition may be subjected to a temperature of about 200 F.without impairment of the leafing property or the luster of the bronzingpowder. Also, the presence of moisture, either in the composition itselfor on the surface to which it is applied, does not impair the appearanceor the effectiveness of the film.

By varying the kinds and amounts of the oil and resin components of thevehicle, the characteristics of the film, such as hardness, andflexibility may be readily controlled, without affecting theleaflngproperty and luster of the bronzin'g powder.

I claim:

1. A composition for mixing with bronzing materials for use in apaint orvarnish vehicle comprising stearic acid, butyl oleate, and diphenylalkyl ester of a monobasic fatty acid, said ester havli'g a boilin p intabove about 212 F., and an agent for inhibiting polymerization ofmaterials contained in a vehicle-when the paste is mixed therewith toproduce a paint.

5. A coating composition comprising a vehicle base containing oil heattreated in the presence of an anti-polymerization agent and containing afatty acid leafing 'agent of the class derived from fats and oils, andan alkyl ester of a monobasic fatty acid said ester having a boilingpoint above about 212 F., and a bronzing powder.

6. A coating composition comprising a vehicle base containing oil andresin heat treated in the presence of an anti-polymerization agent andhaving the property of drying as a hard Permanent film, said basecontaining a fatty acid .leafing agent selected from the groupconsistingof stearic acid and myristic acid, and an alkyl ester of amonobasic fatty acid said ester having a boiling point above about 212'I"., and a bronzing powder.

7. The method of stabilizing a bronzing com- 1 position which comprisestreating the composition with a mixture of a fatty acid leaflng agent ofthe class derived from fats and oils, an alkyl ester of a monobasicfatty acid said ester having a boiling point above about 212 F., and anagent for inhibiting P lymerization of film forming materials containedin-the composition.

8. The method of restoring lost leaflng property and luster to abronzing composition which comprises mixing with the composition amixture comprising a fatty acid leaflng agent selected from the groupconsisting of stearic acid and myristic acid, an alkyl esterpi amonobasic fatty acid, said ester having a boiling point above about 212F., and an agent for inhibiting polymerization of fllm forming materialswith which the hronzing material is mixed.

9. The method of preparing an agent for use in imparting, restoring andstabilizing the properties of leaflng and luster in a bronzingcomposition in which aluminum flakes are mixed with a vehicle containingpolymerizable material which comprises mixing stearic acid, an alkylester of a monobasic fatty acid, said ester having a boiling point aboveabout 212 It, and an anti-polymerization agent, and heating themixture'to about 200 F.

10. A composition for mixing with aluminum bronzing materials forobtaining stable properties of leaflng and luster of aluminum flakeswhen mixed withva vehicle containing polymerizable material whichcomprises a fatty acid of the class derived from fats and oils, and analkyl ester of a monobasic fatty acid having a boiling point above about212 F.

11. A composition for mixing with aluminum bronzing materials forobtaining stable properties of leaflng and luster of aluminum flakeswhen mixed with a vehicle containing p lymerizable material whichcomprises\ a fatty acid of the class derived from fats and oils, analkyl ester of a monobasic' fatty acid having a boiling point aboveabout 212' R, and an agent having the property in the presence of saidfatty acid of inhibiting polymerization of materials contained in thevehicle.

12. A composition for mixing with aluminum bronzing materials forobtaining stability of the property of leaflng of aluminum flakes whenmixed with a vehicle containing polymerizable material which consistsessentially of a fatty acid selected from the gro p consisting ofstearic acid and myristic acid, diphenyl guanidine, and

-a solvent thinner for the fatty acid-and diphenyl guanidine.

13. The method of preparing a bronslng paint having stable leailngproperties which comprises and oils, an anti-polymerization agent havingthe property in the presence of the fatty acid of inhibitingpolymerization of the polymerizable materials, and a thinner which is asolvent for the fatty acid.

15. The method of restoring lost leaflng property and luster to metallicparticles when mixed 'with' a film forming vehicle containingpolymerizable material, which comprises treating the particles with aprepared agent comprising a fatty acid leaflng agent of the classderived from fats and oils in an amount in excess of that normallyrequired to obtain leaflng in a freshly prepared product, an alkyl esterof a monobasic fatty acid, said ester having a boiling point above about212 F., and an agent for inhibiting polymerization of polymerizable fllmforming materials contained in a vehicle for the metallic particles.

16. The method of restoring lost leaflng property and luster to metallicparticles wh ixed with a vehicle containing polym izable film formingmaterial which comprises subjecting the metallic particles to thecombined and conrequired to obtain leaflng in a freshly preparedproduct, and an agent having the property in the presence of said fattyacid of inhibiting polymerization of the polymerizable materials in thevehicle.

17. As a composition of matter, a prepared agent adapted to be mixedwith aluminum bronzing materials for stabilizing the leaflng property ofaluminum flakes after the same are mixed with a vehicle containingpolymerizable material which consists essentially of a fatty acid of theclass derived from fats ond oils, an anti-polymerization agent havingthe property in the presence of said fatty acid of inhibitingpolymerization of the polymerizable material in the vehicle, and asolvent for the fatty acid and anti-polymerization agent, the fatty acidand anti-polymerization agent being dissolved in the agent.

18. As a composition of matter, a preparedagent adapted to be mixed withaluminum bronzing materials for imparting, restoring. and

stabilizing the leaflng properties of aluminum heat treating a vehiclbase containing polymerizabie material with an agent for inhibitingpolywhich comprises mixing with a vehicleccntainingpolymerisablefllmformingmaterialsanda "bronzing powder about2% to 10% of a separate- 1y compounded stabilising compositioncomprismerization of said material, and mixing with the base a fattyacid of the class derived from ing a fatty acid of the class derivedfrom fats flakes in a vehicle containing polymerizable material whichcomprises a fatty acid of the class derived from fat; and oils, diphenylguanidine, and a solvent, the fatty acid and diphenyl guanidine beingdissolved in the solvent in the proportion of about 2 to 3 parts offatty acid to 1 to 2 partsof diplienyl guanidine.

19. The method of stabilizing the leaflng properties of mixed aluminumpaint in which aluminum flakes are mixed with a vehicle containingpolymerizable material which comprises mix- :ing with the paint about 2to 10% of a prepared agent comprising a fatty acid of the class derivedfrom fats and oils, an anti-polymerization agent having the property ofacting in the presence of the fatty acid to inhibit polymerisation ofpoly OORNILIUS 8. MG.

